As processes for producing 3-acyloxyacrylonitrile compound, the followings are known.
There is an example in which 3-oxopropionitrile compound is reacted with an acid chloride to obtain 3-acyloxyacrylonitrile compound. However, the resulting product is a mixture of E- and Z-stereoisomers, and there is no document in which only either isomer is obtained in a high yield (see, for example Patent Documents 1, 2 and 3).
Although there is a document in which either isomer can be produced by reacting 3-oxopropionitrile compound with an acid chloride, chloro formic acid derivative is merely used as an example and there is no example in which a carboxylic chloride is used (see, for example Patent Document 4).
The process for producing 3-oxopropionitrile compound in which an acetonitrile compound is reacted with an aromatic ester compound is industrially more advantageous than the process for producing 3-oxopropionitrile compound in which an acetonitrile compound is reacted with an aromatic acid chloride.
That is, the advantages are to obviate two steps of hydrolyzing an aromatic ester compound and converting to an aromatic acid chloride, and to be able to reduce the amount of base used by one equivalent compared to the reaction by use of an aromatic acid chloride.
At present, as the process for producing 3-oxopropionitrile compound in which an acetonitrile compound is reacted with an aromatic ester compound, the followings are known.
Non-patent Documents 1 and 2 disclose a production process by use of sodium hydride or lithium/diisopropyl amide in THF solvent. However, a base used is expensive and further dangerous in handling it in an industrial production.
Although Non-patent Documents 3 and 4 and Patent Document 5 disclose a production process by use of sodium ethoxide in ethanol solvent, it occurs a large amount of by-product and thus has a low yield.
Although Patent Document 4 discloses an example in which solid sodium ethoxide is used in toluene solvent, it has a low yield. In addition, Non-patent Document 5 and Patent Documents 6 and 7 disclose processes in which methanol solution of sodium methoxide in toluene solvent or solid sodium methoxide is used and methanol as a by-product is temporarily or continuously distilled off after the reaction or during the reaction. However, the yield of these processes is 38 to 76% and is not so high. Although the yield is improved by removing methanol as a by-product, as the solvent is distilled off together, there are disadvantages that in an industrial scale, it is required to distil off while adding the solvent and therefore procedure becomes tedious, and that a large amount of the solvent is required.
Further, there is a process disclosed in Patent Document 8 in which magnesium alkoxide is used. However, the magnesium alkoxide is expensive, is no universal reagent and is not industrially used.
In addition, as a process in which E-3-acyloxyacrylonitrile compound or a mixture thereof with Z-3-acyloxyacrylonitrile compound is isomerized to obtain Z-3-acyloxyacrylonitrile compound, a process by use of isomerization with light is disclosed (see, for example Patent Document 4). However, a process for obtaining pure Z-3-acyloxyacrylonirile compound by isomerization with an organic base by making use of difference in solubility between E-form and Z-form is not known.    Patent Document 1: International Patent Publication WO97/40009 pamphlet    Patent Document 2: International Patent Publication WO98/35935 pamphlet    Patent Document 3: International Patent Publication WO99/44993 pamphlet    Patent Document 4: International Patent Publication WO01/09086 pamphlet    Patent Document 5: JP 59-110691 A    Patent Document 6: International Patent Publication WO01/29003 pamphlet    Patent Document 7: International Patent Publication WO01/07410 pamphlet    Patent Document 8: International Patent Publication WO01/68589 pamphlet    Non-patent Document 1: J. Org. Chem., 65, 4515 (2000)    Non-patent Document 2: Tetrahedron Lett., 38, 9121 (1997)    Non-patent Document 3: J. Chem. Soc. Perkin trans. I, 1297 (1989)    Non-patent Document 4: J. Am. Chem. Soc., 110, 4008 (110)    Non-patent Document 5: Chem. Pharm. Bull., 30, 1033 (1982)